no this is not free. Because what you would do is setup a "peering" between Snowflake cluster and your own. Even if it is the same region, there is a cost - https://docs.aws.amazon.com/vpc/latest/peering/vpc-peering-b...

That cost acts as a barrier if AWS launches its own Snowflake competitor. Basically AWS taxes you for not using other AWS services, once you are inside AWS.